Stripper assembly for punch presses



. 63,325 Patented Se t. 1a, 1956 i 2,763,325 STRIPPER ASSEMBLY non PUNCH rnnssls Charles E. Wlllous, Eat Orang on Electric Company, Incorporated, New York, N. Y., a corporation of New York June 8, 1953, Serial No. 360,171

3 Chilm. (Cl. 164-110) This invention relates to stripper assemblies for tools used in punch presses and more particularly to pre-loaded spring stripper assemblies for punches and dies which are not equipped with aligning pins.

Stripper assemblies of the conventional types may be mounted readily in punch presses of the long stroke type. Furthermorqin such presses, aligning pins are usually employed to align the punch with the die.

However, in short stroke presses where there are no aligning pins or other conventional means present to assist in mounting the punch and die in the presses, the die setter must visually align the punch and die with each other. Furthermore, the clearance in a short stroke press between the punch and die, when in their open positions,

is insuflicient for the mounting of the conventional stripper assemblies subsequent to the mounting of the punch and die in the press and when the punch and die are mounted simultaneously with a stripper assembly it is extremely diflicult to obtain proper alignment because the stripper assembly obscures the tool setters view of the punch and die opening.

. The object of the invention is 'a stripper assembly, with pre-loaded springs adapted for mounting in a punch press tool subsequent to the mounting of the tool therein.

With this and other objects in view, the invention includes a stripper assembly for a punch and a die of a press, the shipper assembly comprising a member formed to straddle the punch, flexibly supported adjacent the punch and having a stripper plate, sufliciently thin to be moved between the punch and die when in open posit on, secured to the member.

In the present embodiment of the invention, the member of the stripper assembly is U-shaped in general contour having spaced sets of pre-loaded stripper springs on rods provided with grooved elements removably held in apertures of a suitable part of the tool, such as the punch holder, by spring-pressed latches. In this embodiment of the invention, the stripper plate carries grooved pins receivable in apertures of the member where the pins are removably held in place by spring-pressed latches to removably connect the stripper plate to the member.

Other objects and advantages will be apparent from the following detailed description when considered in oJnjunction with the accompanying drawing, wherein:

Figure l is a front elevational view of a press at the end of itswork stroke illustrating the stripper assembly mounted iii the tool;

Fig. 2 is a reduced, isometric, fragmentary detailed. view taken substantially along the line 22 of Fig. 1, and

Fig. 3 is a fragmentary front elevational view of the press in open position, with the stripper assembly in posi-, tion for mounting in the tool.

Referring now to the drawing, attention is first directed to Fig. 1 which illustrates a portion of a short stroke press having a bed 10 and a ram 11, the ram being reciprocated in the usual manner by the conventional driving 5 N. 1., or to West- 2 means not shown. A punch 12 is mounted in a punch holder 14, the punch holder being secured in the conventional manner to the ram 11. The punch holder 14 has been provided with four vertical apertures 15, disposed at desired positions about the punch with lateral openings 16 for a purpose hereinafter described. Spring-pressed plungers 17 are mounted in apertures 18 positioned lat- "erally and opening substantially centrally of the vertical apertures 15. The spring-pressed plungers 17 are held in place by screws 19.

The stripper assembly, particularly adapted for this type of press, may be installed after the punch 12, with i s punch holder 14, is mounted on the ram and aligned with a cavity 20 of a die 21'mounted on the base 10. It

is apparent that anything such as the conventional stripper assemblies, mounted on a punch or punch holder prior to alignment of the punch 12 with the die cavity 20, would render it extremely diflicult for the die setter to quickly and accurately set the punch and die in the press. For

' this reason, the stripper assembly is adapted to be mounted equally for pre-loading between the upper surfaces of the member 24 and the under surfaces of threaded elements 31. The elements 31 are threadedly mounted on the upper threaded ends of the rods 28,'and have grooves 32 therein, annular in general contour and adapted to receive the ends of their respective spring-pressed latches or plungers 17.

A stripper plate 35 with an aperture 36, similar in contour to the cross-sectional contour of the punch 12, and apertures 37 for the heads 29 of the rods 28, is sutliciently thin to be moved between the punch and die when in their open positions, and is suitably rigid to efiiciently strip material 40 from the punch after each punching operation. The stripper plate 35 has a series of grooved pins 41 fixed, as at 42, to spaced portions of the stripper plate with rounded or bevelled upper ends to facilitate their movement into apertures 43 of the-member 24, and annular grooves 44 to receive spring-pressed latches or plungers 45. The plungers 45 are disposed in apertures 46 of the member 24-and are held in place by threaded members 47.

Considering now the setting up of the press and particularly the installation of the stripper assembly, let it be assumed that the die setter has mounted the punch 12 with its holder 14 on the ram 11, and the die 21 with its cavity 20 on the bed 10 in accurate alignment with the punch. This may be done readily as nothing obstructs the view of these parts while being mounted in the press.

When this has been accomplished, the stripper assembly with the pre-loaded springs is moved on the top of the die in a direction so that the member 24 will straddle the punch 12 and the stripper plate 35 will slide beneath the punch. In this manner the stripper assembly is located on the die with the aperture 36 in the stripper plate 35 completes the mounting of the stripper assembly with respect to punch 12. If desired, screws could be employed in place of the latches or spring-pressed plungers 17 and 45. However, the spring-pressed latches have the advantage of saving time and energy in mounting and removing the stripper assembly and also in changing the stripper plate. Although only one type of punch and die and stripper plate has been shown, it is apparent that stripper plates with apertures varying in size and contour for punch and die sets of various sizes and contours may be mounted singly in the stripper assembly and be made a part thereof. Furthermore, if desired, the selected stripper plate may be included in the stripper assembly after the remainder of the-stripper assembly is mounted in place, utilizing also the force of the ram to move the apertures 45 of the member 24 for interengagement with the pins 41.

To remove the stripper plate from the member, a suitable tool may be used to force the pins 41 free of their latches 45 and out of the apertures 43. Also a suitable tool may be moved into the lateral openings 16 to force the elements 31 free of their latches 17 and out of their apertures 15.

It is to be understood that the above described arrangements are simply illustrative of theapplication of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

l. A stripper assembly for a punch carried by a punch holder and a die mounted in a die holder in a short stroke press, the stripper assembly comprising a member of having latch receiving recesses in upper end portions thereof whereby closing of the press will cause the upper end portions of the rods to enter their apertures and be removably held therein by the latches, a sheet metal plate having a thickness less than the stroke of the press, movable between the punch and die when the press is open and having an aperture therein disposed in alignment with the aperture of the member to receive the punch, the member having latch containing apertures therein, and pins having latch receiving recesses therein fixed to the plate and adapted to enter the latch containing apertures of the member while the press is being moved into its closed position to removably connect the plate to the undersurface of the member.

3. A stripper assembly for a punch carried by a punch holder and a die mounted in a die holder in a short stroke press, the stripper assembly comprising a member of greater thickness than the stroke of the press and having an aperture for the punch open through one side of the member whereby the member may be moved laterally to straddle the punch and rest onthe die holder, latch containing apertures in the punch holder, rods 'resiliently carried in aligned apertures of the member, positioned for alignment with their respective latch containing apertures, having shoulders to engage the punch holder and having latch receiving recesses in upper end portions thereof whereby closing of the press will cause the upper end portions of the rods to enter their apertures and be removably held therein by the latches, a sheet metal plate having a thickness less than the stroke of the press, movable between the punch and die when the press greater thickness than the stroke of the press and having an aperture for the punch open through one side of the member whereby the member may be moved laterally to straddle the punch and rest on the die holder, latch containing apertures in the punchrholder, rods resiliently carried in aligned apertures of the member, positioned for alignment with their respective latch containing apertures, having shoulders to engage the punch holder and having latch receiving recesses in upper end portions thereof whereby closing of the press will cause the upper end portions of the rods to enter their apertures and be removably held therein by the latches, a sheet metal plate having a thickness less than the stroke of the press, movable between the punch and die when the press is open and having an aperture therein disposed in alignment with the aperture of the member to receive the punch, and means to removably connect the plate to the undersurface of the member.

2. A stripper assembly fora punch carried by a punch holder and a die mounted in a die holder in a short stroke press, the stripper assembly comprising a member of greater thickness than the stroke of the press and having an aperture for the punch open through one side of the member whereby the member may be moved laterally to straddle the punch and rest on'the die holder, latch containing apertures in the punch holder, rods resiliently carried in aligned apertures of the member, positioned for alignment with their respective latch containing apertures, having shoulders to engage the punch holder and is open and having an aperture therein disposed in alignment with the aperture of the member to receive the punch, the member having latch containing apertures therein, and pins having latch receiving recesses therein fixed to the plate and adapted to enter the latch containing apertures of the member while the press is being moved into its closed position to removably connect the plate to the undersurface of the member, the plate having apertures for the rods disposed in alignment with their rod receiving apertures of the members when the plate is removably secured to the member.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES American Machinist, vol. 93, Issue 24, December 1, 1949, pp. 108-110. 

